Press system

ABSTRACT

Disclosed is a press system having advantages of preventing a molded product panel from bursting or being torn due to a difference in molding depth caused by a protrusion shape to improve the moldability and marketability of the product panel when press molding is performed on a material panel. An illustrative press system comprises: a lower die punch provided on a bolster and having a lower surface shape of a product panel; a blank holder provided on the outside of the lower die punch and mounted on the bolster through cushion pins; an upper die having an upper surface shape of the product panel, mounted on the slider, and pressing a material panel together with the lower die punch to mold the product panel; and a sub blank holder unit provided inside the lower die punch by performing the molding while holding a portion of the material panel to be molded into a protrusion shape together with the upper die such that a difference in molding depth is compensated when molding is performed.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of Korean Patent Application No. 10-2010-0123462 filed in the Korean Intellectual Property Office on Dec. 6, 2010, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

(a) Field of the Invention

The present invention relates to a press system, and more particularly, to a press system preventing a molded product panel from bursting or being torn due to a difference in molding depth caused by a protrusion shape when a material panel is molded.

(b) Description of the Related Art

In general, a vehicle maker produces a vehicle by assembling about 20000 to 30000 components through several assembly processes.

Particularly, product panels are produced through various kinds of press systems in the first stage of a vehicle manufacturing process, and is transferred to a vehicle body factory where each portion of the product panels is assembled to form a vehicle body in body in white (B.I.W).

As described above, in order to mold a material panel into a product panel, averagely, four press molding processes are performed, including a draw molding process, a trimming and piercing molding process, a cutting and piercing process, and a flanging and piercing process. The draw molding process is a major process which plastically processes a material according to product data and determines 90% or more of the quality of a panel component.

In a general press system applied to the draw molding process, as shown in FIG. 1, a lower die punch 101 having a lower end surface shape of a product panel is mounted on a lower bolster 103. On the outside of the lower die punch 101, a blank holder 107 is mounted on the bolster 103 through cushion pins 105.

Further, an upper die 111 having an upper end surface shape of the product panel is mounted on an upper slider 109 over the lower die punch 101, and a material panel 113 lies on the blank holder 107 between the upper die 111 and the lower die punch 101 and is pressed to form a product panel.

That is, as shown in S1 of FIG. 1, first, the panel 113 is inserted between the upper die 111 and the lower die punch 101 and the panel 113 is put on the blank holder 107.

In this case, the upper die 111 descends such that the edge of the panel 113 is held by a dieface surface of the upper die 111 and a dieface surface of the blank holder 107 as shown in S2 of FIG. 1, and the upper die 111 and the blank holder 107 descend together as shown in S3 of FIG. 3 so as to plastically process the panel 113 into a product panel by press molding, as shown S4 of FIG. 1.

However, the general press system has a problem in which the product panel bursts or is torn at a portion molded in a protrusion shape due to a difference in molding depth in a case of molding a material panel integrally with a protrusion shape such as a spoiler applied to a tail gate of a hatchback style vehicle or an RV vehicle.

Therefore, the general press system involves problems in which when a material panel is molded, the depth of the protrusion shape is restricted to reduce moldability, a separate additional structure should be mounted to implement the protrusion shape to increase the cost, and the marketability of the molded product panel is reduced.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.

SUMMARY OF THE INVENTION

The present invention has been made in an effort to provide a press system having advantages of preventing a molded product panel from bursting or being torn due to a difference in molding depth caused by a protrusion shape to improve the moldability and marketability of the product panel when press molding is performed on a material panel.

An exemplary embodiment of the present invention provides a press system including: a lower die punch provided on a bolster and having a lower surface shape of a product panel; a blank holder provided on the outside of the lower die punch and mounted on the bolster through cushion pins; an upper die having an upper surface shape of the product panel, mounted on the slider, and pressing a material panel together with the lower die punch to mold the product panel; and a sub blank holder unit provided inside the lower die punch by performing the molding while holding a portion of the material panel to be molded into a protrusion shape together with the upper die such that a difference in molding depth is compensated.

The sub blank holder unit may include a mount plate mounted on one side of an upper portion of the bolster, a sub blank holder provided inside the lower die punch to be sildable and holding a portion of the material panel, and at least one elastic member provided between the mount plate and the sub blank holder and providing elastic force to the sub blank holder.

The elastic member may be made of a gas-cylinder-type spring.

The elastic member may be provided in plural, and the plurality of elastic members may be mounted at equal intervals between the mount plate and the sub blank holder.

According to the exemplary embodiments of the present invention, it is possible to prevent a product panel from bursting or being torn due to a difference in molding depth caused by a protrusion shape when press molding is performed on a material panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view illustrating operation states of a general press system in stages.

FIG. 2 is a cross-sectional view of a press system according to an exemplary embodiment of the present invention.

FIG. 3 is a view illustrating operation states of the press system according to the exemplary embodiment of the present invention in stages.

DESCRIPTION OF SYMBOLS

1 . . . Lower die punch;

3 . . . Bolster;

5 . . . Cushion pin;

7 . . . Blank holder;

9 . . . Slider;

11 . . . Upper die;

20 . . . Sub blank holder unit;

21 . . . Mount plate;

23 . . . Sub blank holder;

25 . . . Elastic member; and

P . . . Material panel.

DETAILED DESCRIPTION OF THE EMBODIMENTS

An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings.

Exemplary embodiments described in the present specification and a configuration shown in the drawings are just an exemplary embodiment of the present invention, but are not limited to the spirit and scope of the present invention. Therefore, it should be understood that there may be various equivalents and modifications capable of replacing them at the time of filing of the present application.

Also, it is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). As referred to herein, a hybrid vehicle is a vehicle that has two or more sources of power, for example both gasoline-powered and electric-powered vehicles.

FIG. 2 is a cross-sectional view of a press system according to an exemplary embodiment of the present invention.

In the press system according to the exemplary embodiment of the present invention, as shown in FIG. 2, a lower die punch 1 having a lower surface shape of a product panel is mounted on a lower bolster 3. On the outside of the lower die punch 1, a blank holder 7 is provided on the bolster 3 through cushion pins 5.

Further, an upper die 11 having an upper surface shape of the product panel is mounted on an upper slider 9 over the lower die punch 1, and a material panel P is put on the blank holder 7 and is pressed to form the product panel.

Here, the press system according to the exemplary embodiment of the present invention includes a sub blank holder unit 20 provided inside the lower die punch 1.

The sub blank holder unit 20 is provided inside the lower die punch 1 to perform the molding while holding a portion of the material panel P to be molded into a protrusion shape together with the upper die 11.

Each blank holder 7 holds the edge of the material panel P and then the sub blank holder unit 20 performs the molding while holding the portion to be molded into the protrusion shape together with the upper die 11 descended by the slider 9.

That is, the sub blank holder unit 20 holds the portion of the material panel P to be molded into the protrusion shape so as to adjust an input amount of a material (the amount input when the material is molded), thereby compensating a depth difference between a deeply molded portion and a shallowly molded portion in a product panel having a protrusion shape.

The sub blank holder unit 20 includes a mount plate 21, a sub blank holder 23, and an elastic member 25.

First, the mount plate 21 is provided on the bolster 3.

The sub blank holder 23 is provided to be slidable upward and downward in the lower die punch 1, and holds a portion of the material panel P together with the upper die 11.

Further, at least one elastic member 25 is provided between the mount plate 21 and the sub blank holder 23 and provides elasticity to the sub blank holder 23.

Here, each elastic member 25 may be made of a gas-cylinder-type spring.

Further, elastic members 25 are spaced apart from each other at predetermined intervals and are mounted at equal intervals between the mount plate 21 and the sub blank holder 23. In the present exemplary embodiment, three elastic members are mounted at equal intervals.

Hereinafter, the operation and effect of the press system according to the exemplary embodiment of the present invention configured as described above will be described in detail.

FIG. 3 is a view illustrating operation states of the press system according to the exemplary embodiment of the present invention in stages.

First, as shown in S10 of FIG. 3, the upper die 11 rises by the slider 9 and both blank holders 7 rises from the lower die punch 1 by the cushion pins 9,

In this case, the sub blank holder 23 of the sub blank holder unit 20 maintains a state in which the sub blank holder 23 has risen from the lower die punch 1 together with each blank holder 7 by the elastic member 25.

In this state, a material panel P is inserted between the lower die punch 1 and the upper die 11 and is put on the blank holders 7 and the sub blank holder 23.

Thereafter, the upper die 11 descends by the slider 9 and thus the edge of the material panel P is held by a dieface surface of the upper die 11 and a dieface surface of the blank holder 7 as shown in S20 of FIG. 3.

In the state in which the edge of the material panel P is held by the blank holders 7 and the upper die 11, the upper die 11 continuously descends. Here, the sub blank holder 23 holds a portion of the material panel P to be molded into a protrusion shape on the upper die 11 as shown in S30 of FIG. 3.

In this state, the upper die 11 and the blank holders 7 lower together to press the material panel P against a mold surface of the lower die punch 1 as shown in S40 of FIG. 3. Therefore, the material panel P is plastically processed into a product panel by press molding, as shown in S50 of FIG. 3.

That is, the blank holders 7 and the sub blank holder 23 sequentially hold the material panel P on the upper die 11 so as to adjust an input amount of a material before molding starts. Therefore, a difference in molding depth in the material panel P is compensated and moldability is secured through volume securement.

Therefore, according to the press system according to the exemplary embodiment of the present invention configured as described above, it is possible to prevent a molded product panel from bursting or being torn due to a difference in molding depth caused by a protrusion shape when the material panel P is pressed.

Further, the press system according to the exemplary embodiment of the present invention holds one side of the material panel P to be molded into a protrusion shape through the sub blank holder unit 20 configured inside the lower die punch 1 so as to perform the molding with a material input amount adjusted. Therefore, the difference in molding depth caused by the protrusion shape can be compensated so as to improve moidability and improve the marketability of the molded product panel.

While this invention has been described in connection with what is presently considered to be practical exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 

1. A press system comprising: a lower die punch provided on a bolster and having a lower surface shape of a product panel; a blank holder provided on the outside of the lower die punch and mounted on the bolster through cushion pins; an upper die having an upper surface shape of the product panel, mounted on a slider, and configured to press a material panel together with the lower die punch to mold the product panel, a portion of the material panel to be molded into a protrusion shape; and a sub blank holder unit provided inside the lower die punch and configured to hold the portion of the material panel to be molded into the protrusion shape together with the upper die such that a difference in molding depth is compensated.
 2. The press system of claim 1, wherein the sub blank holder unit includes a mount plate mounted on one side of an upper portion of the bolster, a sub blank holder provided inside the lower die punch to be slidable and holding a portion of the material panel, and at least one elastic member provided between the mount plate and the sub blank holder and providing elastic force to the sub blank holder.
 3. The press system of claim 2, wherein the elastic member is made of a gas-cylinder-type spring.
 4. The press system of claim 2, wherein the elastic member is provided in plural, and the plurality of elastic members are mounted at equal intervals between the mount plate and the sub blank holder.
 5. A method, comprising: inserting a material panel on a blank holder between a lower die punch and an upper die, the lower die punch having a lower surface shape of a product panel, the blank holder provided on the outside of the lower die punch, and the upper die having an upper surface shape of the product panel; pressing the material panel between the upper die and lower die punch to mold the product panel, a portion of the material panel to be molded into a protrusion shape; and compensating a difference in molding depth between the upper die and lower die punch at the protrusion shape using a sub blank holder unit provided inside the lower die punch and configured to hold the portion of the material panel to be molded into the protrusion shape together with the upper die.
 6. The method of claim 5, wherein the sub blank holder unit includes a mount plate mounted on one side of an upper portion of the bolster, a sub blank holder provided inside the lower die punch to be slidable and holding a portion of the material panel, and at least one elastic member provided between the mount plate and the sub blank holder and providing elastic force to the sub blank holder.
 7. The method of claim 6, wherein the elastic member is made of a gas-cylinder-type spring.
 8. The method of claim 6, wherein the elastic member is provided in plural, and the plurality of elastic members are mounted at equal intervals between the mount plate and the sub blank holder.
 9. A press system comprising: a lower die punch having a lower surface shape of a product panel; a blank holder provided on the outside of the lower die punch; an upper die having an upper surface shape of the product panel and configured to press a material panel together with the lower die punch to mold the product panel, a portion of the material panel to be molded into a protrusion shape; and a sub blank holder unit provided inside the lower die punch and configured to hold the portion of the material panel to be molded into the protrusion shape together with the upper die such that a difference in molding depth is compensated.
 10. The press system of claim 9, wherein the lower die punch is provided on a bolster, the blank holder is mounted on the bolster, and the upper die is mounted on a slider.
 11. The press system of claim 10, wherein the sub blank holder unit includes a mount plate mounted on one side of an upper portion of the bolster, a sub blank holder provided inside the lower die punch to be slidable and holding a portion of the material panel, and at least one elastic member provided between the mount plate and the sub blank holder and providing elastic force to the sub blank holder.
 12. The press system of claim 11, wherein the elastic member is made of a gas-cylinder-type spring.
 13. The press system of claim 11, wherein the elastic member is provided in plural, and the plurality of elastic members are mounted at equal intervals between the mount plate and the sub blank holder. 